I Want to Grow Old with You
by muaaimoi
Summary: In which Penny finds that honesty is hard. Sheldon readily, and unknowingly agrees.Set in season 5. After The Infestation Hypothesis. S/P love! R&R
1. Chapter 1

**I Want to Grow Old with You**

**_By: muaaimoi_**

xXx

She hadn't meant it.

It doesn't even bother Penny until she has to cough up ten more bucks for the bum to get rid of the chair. Then she's left home alone, Amy having gone to get her shots, twenty bucks poorer than when she had started, and feeling remarkably stupid. It's not exactly a new feeling.

But sitting exactly where she'd sat before Sheldon had freaked out about the chair, and reliving the moment…It bothers her.

Penny hadn't been very close to her maternal Grandparents growing up. All she really remembers is the way they fought all the time. Her father had hated it. He said it was an awful example of what married life could be like. Penny's mother would just shake her head, sigh, and say " Bob if they haven't killed each other in fifty years they aren't going to chose tonight to do it. " But she had given up eventually. She knew her mother still spoke to her parents on the phone. But they had stopped spending time together, the way family should.

As always, her mother had given in.

Penny had always hated that. Because even among the memories of countless arguments, many of them run through like a script, there had been other moments Penny remembered too. Few and far in between, but much clearer than any argument.

Like the one time her grandfather had fallen asleep at the chair. Her grandmother had sat right beside him with a huff, and Penny had watched in confusion as her grandmother twined their fingers together. Mumbling , all the while, about forgetful old fools. It hadn't been long until she had fallen asleep too. It had been surprisingly cute. Watching the way they leaned into each other, even asleep. Still in love, fifty years later.

It was certainly a better example of marriage than Penny's own parents. With the way her father went about making all the big decisions, and the way her mother just didn't argue. She just let him set their course. She had promised herself she would never be like her mother.

It hadn't even occurred to her that she could have ended up like her grandmother instead.

With the way she and Sheldon argued. The biting comments and weird sync they could always find with each other.

That comfort she never felt with anyone else…

It never mattered to Sheldon what she looked like, how much skin she was showing, or how messy her hair was. He'd made his peace with the lack of cleanliness in her apartment years ago. Hell, he'd made his peace with everything about her that bothered him, period. It didn't mean he was quiet about it. But he wouldn't be Sheldon if he didn't complain, so she dealt with that as best she could. Which was by complaining right back.

At the end of the day, to him, she was just Penny. And she liked that.

Life with Sheldon wouldn't have been hard. Frustrating and wracked with arguments, maybe, but not hard.

And maybe they had reminded her of an old married couple for a moment. Just not her grandparents.

So she hadn't meant it.

She hadn't.

xXx

Sheldon allows himself to smirk in the safety of his room.

He wondered at how easily his so called friends forgot about his Vulcan hearing. Admittedly, he didn't often bring it to their attention, but it was hardly a secret. He was awful at keeping those.

But he supposed he could leave Penny in peace about the foul garbage chair. It was gone after all. And the years of being Penny's neighbor had taught him that some victories where best celebrated and gloated over in private.

For all of her disorganized tendencies, Penny wasn't actually a slob. So he knew the living room would be disinfected in the near future. Not to his standards granted, but Penny wasn't someone he expected exceptional cleanliness from regardless. Perhaps he might sneak in and do a better job.

Leonard was probably too busy with Priya to notice this time.

He was rather enjoying their long distance relationship. Leonard got to satisfy his need for emotional intimacy, and aside from having to leave the apartment at times, Sheldon didn't see a down side. He found he liked Priya a lot more when she wasn't around.

Though, Penny had been acting rather strange lately. Their relationship was as it always was. With Penny attempting to bring chaos into his life and his doing the best to resist it. But that was about the only relationship that had lasted exactly as it was over the years.

Leonard was only his best friend by default now. Amy would have been his preferred choice, but she was female. That meant, for some emotional reason that escaped him, that she wanted to be his girlfriend instead. He'd allowed it, if only not to lose her. People who understood him and were worth a sustained acquaintance were very rare. He hadn't even realized how much he wanted her in his life until she'd almost left him.

And no amount of Cats had been able to replace her. He didn't understand why he'd gone for something Leonard seemed sure would work. At least Sheldon had assumed he was confident about how well a cat could replace women in his life. It had always been his coping mechanism of choice. Well that and sad songs. Perhaps one had to listen to a ridiculous amount of My Chemical Romance to enable the technique to work?

Sheldon didn't know. He had never felt inclined to. And Amy was in his life once again, which meant that he'd just spent valuable seconds of his life on a pointless train of thought.

Leonard was a terrible influence on him.

Just that morning he'd caught himself picturing Penny and himself as an older couple. Like his Pop and Meemaw had been, before colon cancer had claimed his grandfather. They had always been teasing each other back and forth. Sometimes his grandfather would hide Meemaw's things, just to get a rise out of her. It had been his grandfather who had taught him all about practical jokes.

Sheldon had pranked Missy mercilessly around the anniversary of his Pop's death. It was the only way his Meemaw would crack a smile.

And if he could picture himself, sitting in his spot with Penny beside him, a few years down the line, watching star trek, well… it didn't matter.

He was dating Amy after all, and she should be the one who he pictured himself beside.

_**XXX**_

_**Ok .So I know I should be working on my other stories…but this one was begging to be finished. What do you guys think? Should I try to stretch this into a three shot? Or leave it as a one shot and resume my labor on my current multy chapter stories?**_


	2. Chapter 2

**I Want to Grow Old with You**

_**By: muaaimoi**_

xXx

It's too soon when she finds herself alone with Sheldon yet again.

"So..." Penny ventures, she's never done terribly well with silence." How do you think Leonard and Amy are doing at the wedding?"

She doesn't know what she's doing.

She's just bored really, and maybe the tiniest bit lonely. It's like she can never find much to do with herself in her off time lately. So she had found herself in the guy's apartment. And she wasn't quite up to leaving just yet. So what if Sheldon looked stupid, wearing a train conductor hat? And that she feels dumber just watching him. It's not late enough for a bottle of wine quite yet. And she had been starting early just a bit too often lately.

But seriously, what grown man likes model trains so much?

"Penny, please desist in attempting to engage me in conversation. I am much too busy having fun."

Sheldon that's who, Penny thinks. And she can't quite wipe the incredulous look from her face." What's so fun about model trains?"

Penny knows better than to ask. But she wouldn't be Penny if she could help herself. Bad impulse control was one of her strongest character traits. It had her voluntarily sharing space with Sheldon didn't it?

"I believe the best answer to your question would be; what about model trains isn't fun?"

She shakes her head, all fond exasperation and not a little amusement. Really, only Sheldon could get away with something like that.

Of course he ruins the moment by rambling on, oblivious there had been one in the first place.

"A truly perplexing question would be what you find so appealing about Hello Kitty."

And he did not just go there.

Quite suddenly it's on, like Donkey Kong. And if Penny has another flash back to her grams and her grandfather arguing over the color of their drapes, well... It's been happening so often lately it's gotten a lot easier to ignore.

xXx

Its twelve minutes into the argument that Sheldon realizes that he's enjoying it.

It shouldn't be that surprising. Sheldon has always enjoyed arguing. There was always something very satisfying about crushing another's logic with the sheer superiority of his own.

But with Penny, there is no logic to be found, let alone crush.

It's a battle of wills he doesn't engage in with anyone else. He doesn't always manage to win, but paradoxically, this makes it all the more appealing. There is an added thrill of uncertainty that all his other social interactions lack.

They don't even fight that often. Or at least, nowhere near often enough in Sheldon's not quite humble opinion. Penny is always far too busy with some other happenings in her life to make a real go at it. Her love life, some financial crisis, her attempt to date Leonard, and most recently what appear to be feelings of inadequacy.

All things which would make Sheldon feel guilty for adding to her problems. And thus staying his hand and keeping him from properly baiting her. So that they could have another true battle, the kind that was worthy of his genius. What Penny lacked in intelligence she more than made up for in sheer cunning.

It made her his lone worthy opponent. If he wasn't sure that Kripke, Wheaton, and winkle would run behind the law at the first sign of breaking and entering, he would have shown them who was boss long ago.

Penny was always up for a challenge. And something about a ruthless female was very appealing.

Penny is always at her most attractive when they fight. Her green eyes darken and flash, her face gains a flush that high lights her cheek bones. There's even a reddish tint to her lips when she purses them. No amount of shorts, tank tops, or tight clothing ever has ever garnered the same reaction from his biology.

And if he grits his teeth more out of self control than rage, well…

It is something no one else will ever know.

xXx

"Urgh!" Penny groans, throwing her hands up in frustration, "Why do I bother?"

They have gone from arguing about why 'Hello Kitty was awesome and Model Trains weren't' or vice versa, to yet another round of 'Is Sheldon Lee Cooper crazy?'. With Penny as the prosecutor with a resounding yes, and Sheldon on the defense clinging to his 'my mother had me tested excuse'.

It's getting pretty fucking old.

"It is a mystery to me" Sheldon agrees, snidely, "Especially when you know you're going to lose."

Then his eyes widen. Because unlike the last seventeen times they have had this argument, Penny doesn't storm dramatically out of the apartment. Slamming their door and her own, for effect. Instead she smirks.

A sure sign of trouble if Sheldon has ever seen one. A childhood with a twin sister had educated him quite thoroughly about the dangers of smirking females. He had a feeling Penny was about to give him another crash course.

Penny proves Sheldon right. She brings her hand palm out, in full view of Sheldon, and licks it. His child hood in Texas had warned Sheldon all about situations like this as well.

He turns to run. His room has always served him well as a haven from bullies; surely it will save him from Penny as well.

But Penny hadn't spent her own childhood in Junior Rodeo for nothing. And she tackles him to the ground before he makes it past the Kitchen Island.

Penny takes his shrieks as she rubs her wet palm on him as further proof of his insanity. She knows guys who would kill for her to straddle them and touch them with her wet palm. Spit slick or otherwise. She can't help but smile though, Sheldon has the best reactions to teasing she has ever seen.

Even if he would call what she does to him torture.

It's his entire fault though. He really shouldn't make it so fun.

**_XXX_**

**_So part three's already a little dirtier than this, and Ive barely started it. Should I just change the rating and do some smut?_**


	3. Chapter 3

**I Want to Grow Old with You**

_**By: muaaimoi**_

xXx

It's just another day.

And yet another argument with Sheldon. The guys have gone ahead to the movie theater; the timing and placing of the movies have once again earned them a Sheldon free outing. Penny had been invited to come along.

It had pretty much been established that she wouldn't when she hadn't even heard the door shut.

They are having a stare down when Penny realizes something is very wrong.

She had shifted her weight to her right leg when she felt it. And promptly forgotten whatever it was they had been arguing about.

She hadn't even noticed beforehand. Far too busy crossing her arms, and glaring back at Sheldon. She wishes she was that oblivious now. Usually when she argues with Sheldon he has her full attention. Her eyes are far too busy drinking in six feet something of angry Texan genius to bother with anything else. And her rage with Sheldon has always been all consuming. Visceral, really.

As much as Sheldon has all of her attention when they argue, she has all of his as well. And a genius's full attention is nothing to sneeze at. Sheldon's eyes bore into her, the entirety of his big beautiful mind takes a break from figuring out the mysteries of the universe and focus on her. Penny, the waitress from Omaha, Nebraska. The actress wanna-be who has yet to be good enough for any real part.

And when she fights with him, Penny becomes the sole object of his focus.

Sometimes Penny wonders if that's what being under a spotlight feels like. And some part of her has always been afraid to find out. It's much too tempting.

If sometimes she feels a little extra moisture when she gets home after, well… Penny has always had a healthy libido. It's not exactly something she has ever thought to attribute to fighting with Sheldon.

Except that now, there's no denying it. Because she can feel her body reacting. Her nipples are much harder than they should be, and that heat in her belly is definitely not all rage.

Penny flushes with shame. This is Sheldon, Amy's Sheldon. And here Penny was, lusting after her besties boyfriend, how skanky was that?

"Penny" Sheldon all but growls at her, his voice drooping into a baritone that Penny now realized she liked far too much. Just why did she have to start paying attention?

Penny tugs on her hair in frustration. This just can't be happening. Arguing with Sheldon doesn't get her hot. It doesn't! It's against the laws of the universe for her to find him attractive. No matter how cute she sometimes thought he was.

"Penny!" Sheldon growls again, and this time it can be called nothing but. He'd approached her at some point, probably when Penny was far too busy in her head, and he's far too close.

"What?" She snaps, stepping forward when all her working brain cells are screaming at her to step back.

Sheldon's eyes flash gloriously and Penny has a hard time remembering that she doesn't like him. She can't. He's Amy's, _Amy's_!

"Are you _giving up_?" Sheldon almost sounds insulted. As if Penny not fighting with him until her last breath was offensive.

"No way in hell!" Penny snarls, even if she can't quite remember what they had been fighting about.

They're almost nose to nose now, close enough that Penny can make out the ring of grey around Sheldon's iris. Much, much too close. She shouldn't be looking into his eyes like this. He's forbidden property. _Amy's_ property.

"Good" Sheldon says softly, more a breath than anything else. And then he smirks at her. Slow, infuriating, and so fucking sexy. Penny could not be held responsible for her actions. She was sure Sheldon would have said he belonged to no one but himself, anyway.

xXx

Sheldon isn't prepared to have Penny kiss him.

Like most of the kisses he'd experienced thus far in life it was a surprise attack. Sheldon had been enjoying their argument, as was his habit, when Penny had paused.

He hadn't quite been able to classify what human emotion her widened eyes and quickened breath signified, but he had known it was pulling her attention away from the subject matter at hand. And that was inexcusable.

So he had taunted her. Sheldon thought he had gained the desired result when she had snarled at him. And next thing he knew Penny had seized his collar and fused their lips.

He can't quite help but freeze. Caught with his proverbial pants down. It was embarrassing, he doesn't know what to do. It's something that, no matter how many dreams he's had, he hasn't planned for.

But that doesn't mean he couldn't improvise.

It was a very pleasing experience. And definitely something worth working out. Not to mention working _on_.

Penny's lips were soft yet firm, and it was very clear who was kissing who. It was the only point Sheldon could find any contention with. So he decided to change it. Grasping Penny's cheek with his palm and holding her face still as _he _kissed _her._

And that was much better.

Only Penny seemed to prefer it the other way around. Which led to a whole different kind of arguing. And one Sheldon truly thought he could really begin to prefer. Especially once his arms dropped to her waist and he leaned down, tilting his head for better access.

And then Penny's tongue moved in a way that was all sorts fascinating and Sheldon found it very hard to do any thinking at all. Dueling his tongue with her own in a way that had Sheldon gasping into her mouth.

It was all he could do to pull her towards him. Grasping her hips and losing himself in the sensation of having Penny give him her all.

xXx

Kissing Sheldon would have to go down as the most satisfying action of her life.

Ever.

The feeling of rightness, and blissful pleasure were almost second to a wave of sheer satisfaction at owning the crazy Physicist lips with her own.

Almost.

And that wasn't even touching on how hot it was. Penny feels impossibly wetter when he begins to kiss back. His hands on her hips are gripping with a strength she hadn't known he had. It was time to give up the goat, so to speak. Sheldon cooper was definitely turning her on.

And like most things Sheldon tried his hand at, he was good at it. He seemed to get better at kissing every passing second. Until Penny had to pull out all the tricks she had just to dominate the kiss. And she was still rapidly losing ground. With the way Sheldon was touching her, his hands skimming under her shirt.

One hand slipping into her shirt. Crawling teasingly slowly, past her stomach, then the bottom of her breasts, until Sheldon was out right groping her. Penny moaned in approval, bringing her own hands to grab at his surprisingly toned ass. Clearly walking four flights of stairs every day wasn't just good for her thighs.

Sheldon soon made the same discovery by slipping his other hand into her pants.

Penny groaned. Sheldon's large palms easily covered her ass cheek, and his long fingers dug deliciously into her flesh, brushed against her wet center.

"Oh" Sheldon whispered against her lips. His eyes were trained on her face, completely enraptured by her reaction. He slid his hand out of her pants. Fingers deftly making quick work of her button and zipper. Penny had no trouble shimming right out of them. And Sheldon had no problem cupping the whole of her pussy roughly. Rubbing at her clit with his fingertips before slipping his fingers inside her. And the new angle just felt so _good_.

"Sheldon" Penny gasped into his neck as he slid two of those long fingers inside her. Her knees buckled.

She hooked a leg around him. Wrapping her arms around his neck in a vain attempt to stay on her feet. All it did was bring her thigh into full contact with Sheldon's cock. Straining valiantly against his ugly plaid pants and emanating a heat Penny desperately craved inside her.

xXx

Penny was so incredibly wet. Sheldon knew it was a sign of her arousal. If he could manage any kind of focus he could have probably recalled much more on the subject. As it stood, with most of his blood focused on lengthening his phallus all he could really think was _fascinating_.

Every thrust of his fingers inside her elicited a sound that went straight to his groin. He had never been so hard in his life. And as Penny clutched at him and moaned decadently he became impossibly harder.

Penny was leaning heavily on him. And Sheldon's own knees were beginning to feel weak as he began to lose himself in Penny's wetness and heat. The need to sear that heat with his own pulsed with every heart beat. The need to be inside her was perfectly compelling. And the where didn't matter anywhere near as much as the how.

Sheldon lowered them to the ground. Willing himself to go slowly, lest he lose his rhythm as he finger fucked Penny. He had slipped three fingers inside her, and couldn't quite control himself any longer.

Penny looked up at him, a look of wanton desire on her face as she spread her thighs invitingly. It snapped what was left of his self restraint.

After, Sheldon wouldn't remember how he'd managed to rid himself of him pants, or his underwear. All he knew was that one moment is hand was buried between Penny's thighs, and then it was his cock.

It made everything worth it. The subdued desires. The late nights when he'd actually struggled to rest. The iron clad grip he'd had to put on his libido lest he become a drooling moron after Penny, like the rest of his friends. All of it was worth it.

All for the pleasure of it. Of slamming into Penny with abandon and having her meet his every thrust. Having Penny's nails dig gauges into his back as he gripped her hips hard enough to bruise. To have it all feel so unbelievably _good…_

It was better than solving any equation. The rightness of it, man to woman, lips to lips, Penny to Sheldon.

He lost all sense of time. The rest of Pasadena could have been invaded by zombies and Sheldon wouldn't have cared. An alternate version of himself with proof of string theory could have materialized right beside them and he wouldn't have noticed.

He didn't know what to call what they were doing. Not coitus, or sex or even fucking. But whatever it was, in the center of his living room, as he and Penny became one she was the complete center of his universe.

And he rather thought neither of them could argue with that.

_**xXx**_

_**So.. whadda ya think?**_


End file.
